what is cement and how it made.

             

       we all know that the cement is a binder material, a substance used for construction that sets, hardens, adheres to other materials to bind them together and make a homogeneous material which is the final product. cement barely used its own because of its limitations.cement mixed with fine aggregate produces mortar for masonry or with sand and course aggregate, produces concrete.

               Raw material for cement
  • Calcareous materials
           e.g   -  lime stone
                   -  chalk
                   -  marl
  •  Argillaceous materials
           e.g  -  clay
  •   There are three processes of cement manufacturing :
  1. wet process
  2. dry process
  3. semi-dry process
  • There are three operations involved in manufacturing of cement.
  1. mixing of raw materials
  2. burning
  3. grinding
  • In the wet process, raw materials are mixed in wet condition in required proportion and slurry is formed. while in the dry process raw materials are mixed in dry condition and dry mix are formed. 
  • In the burning process, the slurry is fed into rotary kiln from the upper end. as the slurry descends gradually from top to bottom, the temperature raises and it converts into small lumps which are known as nodules.
  • These nodules, reach to the burning zone, where temperature is about 1500 C to 1700 C. in burning zone, calcined product is formed and nodules are converted in to small hard balls, known as clinkers. the size of clinkers varies from 3 mm to 20 mm.
  • In the grinding process, these clinkers are finely ground in ball mills and tube mills. A small quantity about 2 to 3 % of gypsum is added to prevent flash setting of the cement.
  • These cement is stored in silos. afterward it weigh and packed into bags by automated machine.
  • Each bag of cement contains 50 kg of weight or 0.035 cum or 1.22 cft of volume.



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